1. Field of the Invention
The present invention is broadly concerned with improved lay-flat book products which can be rapidly and easily manufactured, even with small run quantities, as for example, of the order of 100 to 1,000 copies. More particularly, the invention is concerned with such lay-flat books as well as methods of production thereof, wherein the book is made up of a series of juxtaposed individual sheets each having a binding edge which is notched; the sheets are placed in an alternating relationship with offset notch patterns, and are preferably interconnected by application of a cold set glue into the notches with the thickness of any glue remaining on the spine being insufficient to inhibit the lay flat characteristics of the sheets of the book product. A relatively thin, flexible spine cover is adhesively secured to the spine of the book contents in close conforming relationship to the spine. In one embodiment of the invention, the spine cover is a length of flexible tape having a width somewhat but not substantially greater than the thickness of the contents of the book that is secured to the spine by an adhesive. In an alternate embodiment, the spine cover is U-shaped, flexible paper sheet material having sides equal in area to that of the sheets and a central portion of the same size as the spine. The central portion of the full cover is adhesively secured to the spine of the book contents. The spine cover preferably has a pre-applied adhesive such that the spine cover will closely adhere to the spine of the book contents without interfering with the lay flat opening properties of the book. The books of the invention may be produced in soft or hard cover versions without detracting from the lay-flat capability thereof.
2. Description of the Prior Art
Books and periodicals are commonly bound in a “perfect binding” method wherein a plurality of pre-printed sheets of paper are gathered together in a book block. The uncut spine of the book block is then abraded or notched to create a roughened glue-receiving surface. Glue is applied along the abraded spine and a cover is applied over the book block. Other types of prior binding methods include sewing the signatures together in the well known Smythe Sewn method or attaching the signatures or sheets together with staples.
A significant problem with all of these prior art binding methods is that the books created therefrom do not open fully and lay flat. There are a large number of variables involved in any effort to produce a lay-flat book, book block or booklet, including size and number of pages, quantity and quality of print, reliability and durability of the product, and the different makeup of all plants that choose to produce this type of product with present methods of binding. Specifically, when books created by any of these prior art methods are opened, the pages assume a decidedly arcuate shape adjacent the bound edge, making it difficult for the reader to hold the book open and read the printed text that is adjacent the bound edge. This is a problem with all types of books, but is especially problematic with instruction manuals, cookbooks, workbooks, textbooks, and other types of books that are read while the reader carries on other tasks with his or her hands.
Some prior art attempts have been made to create books that open and lay flat. An early patent to Ryan, U.S. Pat. No. 379,334 of Mar. 13, 1888 illustrates and describes a book composed of sections in which each section is secured to the back separately and thereby flexibly independently of the others leaving the leaves flexible at a line parallel to and at a sufficient distance from the back to allow each to lie flat upon the others when open. However, this method relies upon the concept of creasing the individual sheets making up the book to form separate V-portions, interleaving the creased V-portions, and then joining the V-portions by stitching. The creasing and stitching operations as disclosed in the Ryan '334 patent not only are expensive and largely impractical in high-speed book binding operations, but the appearance of the open book as illustrated in the drawings of the patent is not desirable.
Kadish in U.S. Pat. No. 5,456,496 of Oct. 10, 1995 discloses a book and method of binding in which the pages are described as laying flat upon opening of the book. However, in order to accomplish this desired function, the patentee provides a woven tabbed tubular ribbon with the individual sheets being adhesively attached to the ribbon. The tubular ribbon allows the bound edges of the pages to move away from the spine of the book when the book is open, thus permitting the pages to lay relatively flat. Unfortunately, this and other prior art methods of binding books so that they open flat are complicated, time consuming, and costly and are therefore not economically feasible for many types of printed material.
U.S. Pat. No. 1,715,658 describes the production of check books making use of alternating sheets having offset notches along the binding edges of the sheet. However, these notches are of significant depth and length, and would not be suitable for a lay-flat book of general purpose. Moreover, the use of conventional hot melt adhesives in the production of check books would detract from any lay-flat capability thereof.